1. Field of the Invention
The present invention relates to a liquid discharge head substrate that discharges liquid used to perform recording operation.
2. Description of the Related Art
A liquid discharge apparatus typified by an inkjet recording apparatus performs a recording operation such that thermal energy which energy generating elements generate by performing energization is conveyed to liquid, and the liquid is discharged from discharge ports. Japanese Patent Application Laid-Open No. 11-070658 discusses a configuration for arranging a plurality of energy generating elements 108, which is connected to one connection line 109, in the high density. FIG. 5 illustrates a line layout of a liquid discharge head substrate discussed in Japanese Patent Application Laid-Open No. 11-070658. In a region between the plurality of energy generating elements 108 provided in the liquid discharge head substrate 150, there is provided the connection line 109 to which one ends of the plurality of energy generating elements 108 are connected in common, and each individual lines 102 are provided at the other ends thereof. Furthermore, the connection line 109 and the individual lines 102 are provided so that positions of the energy generating elements 108 are to be equal.
In recent years, to realize recording of high-definition images at high speeds in such a liquid discharge apparatus, there has been a demand for arranging the energy generating elements, which generate thermal energy utilized for discharging liquid, in the high density.
When an attempt is made to arrange the energy generating elements 108 in the high density of 1200 dpi or more as discussed in Japanese Patent Application Laid-Open No. 11-070658, it is necessary to provide a spacing (also referred to as a pitch) between adjacent energy generating elements of about 21 μm. In this case it is necessary to secure a certain amount of distance or more between an individual line 102a of an energy generating element 108a adjacent to the connection line 109 and the connection line 109, to secure electrical reliability. For this reason, when an attempt is made to arrange the energy generating elements 108 in the high density and equally, it is necessary to narrow a width itself of the energy generating elements.
Since the heat is absorbed by an insulating layer at an outer peripheral portion of the energy generating element, a region excluding a certain amount of outer peripheral width of the energy generating element constitutes an effective bubbling region. For this reason, when an attempt is made to provide the effective bubbling region with an equal area, while keeping the width of one side of the energy generating element narrow and keeping an aspect ratio large, it is necessary to make the width of the other side of the heating element long. Such a liquid discharge head not only invites increase in a chip area, but also is necessary to increase energy amount required to energize the energy generating element.